Import skp file into Zbrush

I get a model on http://sketchup.google.com/3dwarehouse/,... great! But I would like to export it for Zbrush (without an another expensive software). It works like that:

1. Download the free Sketchup software
2. Download the Obj exporter from Sketchucation
http://sketchucation.com/forums/viewtopic.php?t=33448
install it
3. Download your model from the warehouse (skp file)
4. Open it in Sketchup, export it als Obj
5. Import the as tool in ZBrush
That's it

i.e.